1. Field of the Invention
This invention relates to measuring instruments, and specifically, to portable digital horizontal inclinometers.
2. Description of the Prior Art
Currently, two types of conventional pendulum inclinometers, one with a damping device and one without a damping device, are used for the measurement of inclination angles. The inclinometer without a damping device is only suitable for static measurement as it takes a long time for the stabilization of the pendulum to obtain a correct angle reading. On the other hand, the inclinometer with a damping device can provide damping of the pendulum to rapidly eliminate its free swing, and thus to realize a continuous dynamic measurement to the inclination angle.
Conventionally, silicon oil or air has been used for damping of the pendulum. However, the damping coefficient of silicon oil decreases greatly with increasing temperature which restricts significantly the operating temperatures of inclinometers utilizing silicon oil. Similarly, using air for damping is not ideal because it requires complicated designs and high machining precision.
In view of the forgoing, a Chinese Pat. App. No. CN00223002.X disclosed a digital inclinometer with magnetic damping, which offers the advantage of stable and fast reading. Unfortunately, the design disclosed therein is not functional for wide angle measurements.